Fig. 1

Metabolic characterization of aged mice. Metabolic measurements were performed in 3-, 6-, 12- and 24-month old C57BL/6 male mice. Non-fasted body weight (a) and blood glucose (b); glucose tolerance tests represented as glucose traces (c, n = 11–15) and incremental AUC (d); insulin tolerance tests normalized to baseline (e, n = 4–5), and 6-h fasted plasma insulin (f). g-h Insulin secretion from isolated islets, under low glucose (low G), high glucose (high G) and 30 mM KCl, represented as insulin concentration (g, with low G condition shown again on smaller scale on the right), and stimulation index relative to low glucose (h). Insulin content was measured following the final KCl stimulation (i). Data represent values for individual mice with mean ± SEM overlaid. Statistical analyses were performed via Kruskal-Wallis test with Dunn’s post-hoc test (a,d,f), or one-way ANOVA (B,G-I) or two-way repeated measures ANOVA (c,e) with Tukey’s post-hoc test (b,c,e,g-i). * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001 vs 3-month old unless other comparison specified